Dendritic fibrous nanosilica supported Zn-based sorbents towards enhanced hot-coal-gas desulfurization: structural design and metal modification

Abstract

Designing suitable carriers of sorbents for hot-coal-gas desulfurization is still a challenging task so far. In this study, dendritic fibrous nanosilica (DFNS) carriers with central radial pore structures were synthesized via microemulsion method, and the formation mechanism was proposed. The mean particle diameter (MPD) and mean surface wrinkle spacing (MSWS) of DFNS could be directionally controlled by regulating the emulsion phase behavior during DFNS synthesis. A series of mesoporous Zn-based desulfurizers were then constructed based on these DFNS carriers. The results indicate that the proposed parameter, pore slope, could be well positively correlated with the breakthrough sulfur capacity of desulfurizers. The activation energy (20.5 kJ/mol) of sorbent with the optimized carrier is significantly lower than that of previously reported desulfurizers. Additionally, the desulfurization performance of DFNS-supported sorbents could be further improved by 1.27%-34.6% by metal (Sm/Mo/Ni) modification. Sorbents with Ni/Zn molar ratio of 1/5 exhibit the highest breakthrough sulfur capacity of 15.85 g S/100 g sorbents. Moreover, the optimized sorbent demonstrated good stability over multiple sulfidation/regeneration cycles, highlighting its potential for hot-coal-gas desulfurization applications.